Hall-mobility anisotropy in GaSe

The Hall mobility has been measured for the first time in a layer compound both along and perpendicular to the layers. The measurements have been extended as a function of temperature and of electrical field by a pulse technique. The results indicate that both mobilities are limited by homopolar optical-phonon scattering and that the effective conductivity masses for holes are different from those derived from time-of-flight measurements. Moreover, the Hall mobility along the $c$ axis is evidently field dependent. It is concluded that stacking faults are responsible for the difference between low-field and high-field mobilities.